1.1 Appearance: the surface of sheet shall be flat and smooth, free of air bubbles, wrinkles or cracks and reasonably free of other small imperfections such as scratches, dents, etc. The edge of sheet shall be tidy and be free of delaminations and cracks. The color shall be substantially uniform, but a few stains are permissible.
1.2 Dimension and allowed tolerance
1.2.1 Width and Length of Sheets
Width & Length (mm) |
Tolerance (mm) |
>970~3000 |
+/-25 |
1.2.2 The nominal thickness & tolerance
Nominal thickness (mm) |
Tolerance (mm) |
Nominal thickness (mm) |
Tolerance (mm) |
0.5 0.6 0.8 1.0 1.2 1.6 2.0 2.5 3.0 4.0 5.0 6.0 8.0 |
+/-0.12 +/-0.13 +/-0.16 +/-0.18 +/-0.20 +/-0.24 +/-0.28 +/-0.33 +/-0.37 +/-0.45 +/-0.52 +/-0.60 +/-0.72 |
10 12 14 16 20 25 30 35 40 45 50 60 80 |
+/-0.82 +/-0.94 +/-1.02 +/-1.12 +/-1.30 +/-1.50 +/-1.70 +/-1.95 +/-2.10 +/-2.30 +/-2.45 +/-2.50 +/-2.80 |
Remarks: For the non-nominal thickness not listed in this table, the deviation shall be the same as that of the next greater thickness. |
1.3 Bending Deflection
Thickness (mm) |
Bending Deflection |
|
1000mm(Ruler length) (mm) |
500mm(Ruler length)(mm) |
|
3.0~6.0 >6.0~8.0 >8.0 |
≤10 ≤8 ≤6 |
≤2.5 ≤2.0 ≤1.5 |
1.4 Mechanical processing: the sheets shall be free of cracks, delaminations and scraps when such machining as sawing, drilling, lathing and milling is applied
1.5 The psical, mechanical and electrcal properties
No. |
Properties |
Unit |
Standard value |
Typical value |
1 |
Density |
g/cm3 |
1.7~1.95 |
1.94 |
2 |
Water absoprtion (2mm sheet) |
mg |
≤20 |
5.7 |
3 |
Flexural strength, perpendicular to laminations |
MPa |
≥340 |
417 |
4 |
Impact strength (Charpy, notch) |
kJ/m2 |
≥30 |
50 |
5 |
Dielectric dissipation factor 50Hz |
— |
≤5.5 |
4.48 |
6 |
Dielectric constant 50Hz |
— |
≤0.04 |
0.02 |
7 |
Insulation resistance ( After 24h in water) |
Ω |
≥5.0 x108 |
4.9 x109 |
8 |
Dielectric strength, perpendicular to laminationsin transformer oil at 90℃+/-2℃, 1mm sheet |
kV/mm |
≥14.2 |
16.8 |
9 |
Breakdown Voltage, parallel to laminationsin transformer oil at 90℃+/-2℃ |
kV |
≥35 |
38 |
The sheets shall be stored in a place where temperature is no higher than 40℃, and be placed horizontally on a bedplate with a height of 50mm or above. Keep away from fire, heat (heating apparatus) and direct sunshine. The storage life of sheets is 18 months from the date of leaving factory. If the storage duration is over 18 months, the product also could be used after being tested to be qualified.
A high speed and small cutting depth g shall be applied when machining because of sheets’ weak thermal conductivity.
Machining and cutting this product will release much dust and smoke. Suitable measures should be taken to ensure dust levels are within acceptable limits during operations. Local exhaust ventilation and using the dust/particle masks are advised.
The sheets are subject to moisture after being machined, a coating of insulating vanish is recommended.